Dual-modification of oxygen vacancies and PEDOT coating on MnO2 nanowires for high-performance zinc ion battery

MnO2 has outstanding potential for application in cathode materials of zinc ion batteries (ZIBs). However, the poor electrical conductivity, poor ion diffusion kinetics, and structural instability greatly limit its rate performance, specific capacity, and cycling stability. Herein, we prepared PEDOT-coated MnO2 cathode material with oxygen vacancy defects, namely Vö-MnO2@PEDOT, by Dual-modification of MnO2 nanowires. The PEDOT coating optimizes the electron transfer capability of the material while inhibiting the dissolution of MnO2. The oxygen vacancies accelerate ion diffusion. Vö-MnO2@PEDOT possesses a joint energy storage mechanism, containing the insertion/extraction of H+/Zn2+ and dissolution/precipitation of MnO2. This joint energy storage mechanism explains the high specific capacity and the increase in capacity. The Vö-MnO2@PEDOT displays a high specific capacity of 400 mAh/g at 0.2 A/g. Besides, at 2 A/g, Vö-MnO2@PEDOT outputs a high capacity of 213 mAh/g after 2000 cycles. This research provides a feasible research idea for the performance optimization of manganese oxide cathode materials.